# Radius of curvature

1. Jan 22, 2006

Hi guys ,I need help to find the radius of curvature for this exercice:

A metal bar is 1.75m long with a coefficient of thermal expansion of 1.34*10-5K-1. It is rigidly held between two fixed beams. When the temperature rises, the metal bar takes on the shape of the arc of a circle.
What is the radius of curvature of the circle when the temperature rises by 40 degrees celcius?

hint:for small angle: sin(x)=x-x3/6.

thankx for your help!

2. Jan 22, 2006

### durt

I'm confident you can find the length of the heated bar. Then, just draw an arc and relate these lengths to the angle of the arc and the radius of curvature. You'll need to use the law of sines, and then you can use the "hint" and solve for the radius.